Klein



A. KLEIN ROD-BALL MILL March 10, 1964 2 Sheets-Sheet 1 Filed June 29, 1961 FIG. 2

FIG.4

INVENTOR. ALEXANDER KLEIN TTORNIIEYE United States Patent Ofiice 3,124,314 Patented Mar. 10, 1964 3,124,314 BBB-BALL MILL Alexander Klein. 351 La Questa Drive, Danville, Califi, assignor of one-third each to Cecil H. Best, Berkeley, Calif., and Lee A. Turzillo, Akron, Ohio Filed June 29, 1961, Ser. No. 120,660 12 Claims. (Cl. 241172) This invention relates to improvements in the construction and operation of rotary grinding mills of the rotary drum type employed for comminuting rock, ores, slag, clinkers and similar materials, and particularly to a novel and improved combination of comminuting elements for use in such a rotary grinding mill, the longitudinal Wall of which may be a desired configuration, as either cylindrical or elliptical in cross section.

An object of the invention is to provide a more effective, efficient and economical grinding mill by a combination of rods and balls as comniinuting elements and by positioning the rods in arcuately aligned layers, one or more layers deep, longitudinally of and contiguous to the longitudinal wall of the rotary grinding mill, and maintaining them in that arcuately aligned position throughout the grinding operation.

Other objects of this invention will become apparent from the following description and the drawing in which FIG. 1 is a perspective view, with parts broken away to illustrate the arrangement of the comminuting rods extending longitudinally of the drum of the rotary mill in definitely arcuately aligned layers contiguous to the grinding surface of the rotary mill and held in alignment, as for example by two annular channels, each channel being contiguous to the said grinding surface of the drum and also to one end member of the cylindrical drum;

HG. 2 is a longitudinal sectional view of the rotary mill shown in FIG, 1;

FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional View similar to FIG. 3, but with a single arcuately aligned layer of rods of which the lead rods are angular in cross section;

FIG. 5 is a longitudinal sectional View of another embodiment of the invention illustrating three arcuately aligned layers of rods and a modified structure of the annular channels;

FIG. 6 is a fragmentary longitudinal sectional view of a further embodiment illustrating the invention applied to a multiple compartment rotary mill;

FIG. 7 is a fragmentary longitudinal sectional view of a still further embodiment of the invention illustrating the rotary grinding mill as frusto-conical in shape and having an abrasion resistant lining and a modified channel forming member; and

FIGS. Sa-e illustrates cross-sectional views of the various types of rods that have been found satisfactory in the rotary grinding mill of this invention.

In the embodiment illustrated in FIGS. 1 to 4 of the drawing, 19 indicates the rotary grinding mill as a whole and is composed of a longitudinal metal wall member 11, the inner surface 12 of which constitutes a grinding surface of the rotary grinding mill 1t), and two circular end members 14, attached to the said wall member 11 by any suitable means to provide the grinding chamber 15. A ring 16, somewhat smaller than the inside diameter of the grinding surface 12 of the wall member 11 is attached to the inner surface of each of the circular end members 14 as by bolts 17, to provide an annular channel 18 at each end of the grinding chamber 15, each annular channel 18 being contiguous to the inner surface 2 of the wall 11 and to an end member 14, the annular channels 18 being generally rectangular in radial cross section.

A plurality of comminuting rods 20 of a length slightly less than the length of the inner surface 12 of the wall 11 are inserted into the grinding chamber 15 in such manner that one end of each rod 20 is positioned in the annular channel 18 at one end of the grinding cham ber 15 and the other end of the rod 20 positioned in the annular channel 18 at the other end of the chamber 15, the rings 16 holding the rods 20 in arcuate alignment along the inner grinding surface 12 of the grinding chamber 15. The channels 18 may be of such width as to hold in position one or more arcuately aligned layers of rods 2%, two such layers of rods 29 being shown in FIGS. 1 to 3 of the drawing, and one arcuately aligned layer of rods 2d being shown in FIG. 4 of the drawing. After the rods 2d have been positioned in arcuate alignment in the channels 18, a quantity of ball type grinding elements 21, such as flint pebbles, iron or steel spheres, and the like, are placed in the grinding chamber 15 and are supported in major part upon the rods 20.

The rods 2% and the balls 21 may be charged into the grinding chamber 15 in any convenient manner. As shown in FIGS. 2 to 4, a manhole 24 is provided in each end member 14 for access into the chamber 15. Likewise, the rotary grinding mill 163 may be rotated by any mechanism, of which many are well known. As shown in H65. 2 to 4, the rotary grinding mill 10 is supported on a plurality of rollers 28, such as the four rollers 28 shown in FIGS. 2 to 4, each of which rollers 23 is supported by a frame post 29. One or more of the rollers 23 may be power-rotated from any power source (not shown), which rotation of the rollers 28 will in turn rotate the rotary grinding mill 10.

It is to be understood that the rods 20 may have any cross-sectional configuration, although rods circular in cross section give satisfactory results. It has been found, however, that rods 2% of the cross section shown in FlGS. 8b, 8c, 8d, and 8e are also highly efficient. A leading rod Zll hexangular, rectangular or triangular cross section, as shown in FIG. 4, provides a scraping action against the inner wall 12 and acts as a further preventive against build-up on the inner wall surface 12 of the longitudinal Wall 11 of the material being comminuted.

The modification of the rotary grinding mill shown in 5 of the drawing embodies fundamentally the sarr construction and mode of operation described above in connection with the embodiment shown in FIGS. 1 to 4. The mill 39 of FIG. 5 has a longitudinal wall member 31 with its inner grinding surface 32 and generally circular end members 34 forming with the wall member 31 a grinding chamber 35. Each end member 34 is attached to an outwardly projecting flange 36 of the wall member 31 as by bolts 37, so as to be readily removable therefrom, and is provided with an outwardly projecting hollow cylindrical shaft portion 38, centrally disposed with respect to the circular end member 34, and serving as the shaft on which the rotary grinding mill 36 rotates. The two shaft portions 33 are rotatably mounted in journals 3%, which are in turn supported by pillars or framework 4%.

An annular ring 41, L-shaped in cross section, is attached centrally to the inner surface of each of the ad members 34- as by bolts 42, the L-shaped ring 41 having a flat annular disc portion 43 and an inwardly projecting circular flange 44 at the outer edge of the disc portion 43, and a central opening 45, preferably as large as the interior diameter of the hollow shafts 38. Between the circular flange 44 and the inner surface 32 of the longitudinal wall 31 is formed an annular channel 46, generally rectangular in radial cross section, in which the arcuately aligned layers of rods 50 are positioned, in the manner above described in connection with the embodiments of FIGS. 2 to 4. Three arcuately aligned layers of rods 50 are 3 shown in FIG. 5, but, as above pointed out, the number of layers of rods St? may be one or more arcuately aligned layers. Balls 51 are charged into the grinding chamber 35, and are of the same type and perform the same function as in the mill of FIGS. 1 to 4.

It is to be understood that the material to be comminuted may be charged into the grinding chamber 35 in any suitable manner and that the rotary grinding mill 30 may be rotated in any of the many ways well known in the art. As shown in FIG. of the drawing, a hopper S4 and a delivery tube 55 are arranged to deliver material to be comminuted through the hollow cylindrical shaft 38 at one side of the mill, and a gear wheel 56 is secured to the outer surface of the hollow cylindrical shaft 38 on the other side of the mill, a spur gear 57, driven by a power source M, meshing with the gear wheel 56 to rotate the rotary grinding mill 30. The comminuting rods 5'0 and the comminuting balls 51 perform the grinding operation in the same way and with the same high degree of efficiency as has been described above in connection with the operation of the rotary grinding mill of FIGS. 2 to 4 of the drawing.

FIG. 6 discloses longitudinal sectional view of a modification of the rotary grinding mill of FIG. 5 of the drawing in that the mill is made up of a plurality of compartments, two compartments 58 and 59 being shown in the drawing, separated by a screen 60, suitably attached to the wall 31, the first compartment 58 receiving the material to be ground, as through opening 45, and breaking it down to a fineness such that it passes through the screen 60 into the second compartment 59 for further comminution to the desired particle size. In the first compartment 58, it may be preferable to use only ball type grinding elements, although both rods and balls may be used in chamber 58 in the manner shown in FIG. 5. In the second compartment 59, any suitable means may be provided for maintaining the rods 61 in arcuate alignment. As shown, a ring 62 attached to the screen 69 provides an annular channel 63 for one end of the rods 61, and a channel 64 in the end plate 65 receives the other end of the rods 61, so as to keep the rods 61 in arcuate alignment during the rotation of the mill. A charge of balls 66 is placed in the compartment 59, upon the rods 61, so as to function as described in connection with the mill of FIG. 5. The parts 31, 32, and 34-49 of FIG. 6 serve the same functions as do like numbered parts of FIG. 5.

The embodiment of the rotary grinding mill shown in FIG. 7 is another modification of the mill shown in FIG. 5, in that the longitudinal wall 68 is frusto-conical in form and has an abrasion resistant lining 70 which may have surface characteristics that facilitate the comminuting action, and in that, further, the L-shaped ring 71, which provides the channel 46, also serves to hold the lining 70 in place and to seal the ends of the lining 70 against penetration of comminuted material in and around the lining 7 0. As shown, the L-shaped ring 71 has a flat annular portion 72, attached to the end member 34, as by bolts 73, and an inwardly projecting wall portion 74 at the inner edge portion of the fiat annular portion 72, the wall portion 74- forming with the end portion of the lining 70 the channels 46 for the positioning and the arcuate alignment of the rods 50, all as more fully described above in connection with FIG. 5.

The rotary grinding mill of this invention in any of the above described embodiments is highly effective in the comminuting of ores, slag, clinkers and of other grindable agglomerates. The one or more arcuately aligned layers of rods extending longitudinally of and contiguous to the longitudinal wall of the rotary drum-type mill are constrained by the channels in the end members of the drum-type mill to roll and/or slide along the inner surface of the longitudinal wall, whereas the balls are free to move and to tumble upon the arcuately aligned rods.

In the above described novel combination of rods and balls, the rods perform a multiple function:

(1) Grind the material being comminuted between the rods themselves, and also between the rods and the longitudinal wall surface of the drum;

(2) Lift the balls up on the ascending side of the grinding chamber to a height at which the balls fall back by gravity on to each other and on to the rods, thus further grinding the material being comminuted between the falling balls themselves and between the balls and the arcuately aligned rods; and

(3) Prevent build-up of the material being comminuted on the inner surface of the longitudinal wall of the drum and on the balls;

(4) Improve the cascading characteristics of the grinding elements; and

(5) Make the speed of rotation of the mill less critical and beneficially alter the centrifuging characteristics of the mill.

The result is a highly eificient rotary mill which is much more effective and economical for the comminuting of material than are the roll mills or the ball mills of the prior art.

It is to be understood that it is not the intention to limit the invention of the claims to the specific constructions hereinabove described and illustrated in the drawing, but that any of Well known means for arcuately aligning the rods, for charging and discharging material into and out of the rotary mill and for supporting, tilting and rotating the drum-type mill may be employed without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

l. A drum-type rotary grinding mill having, in combination, a longitudinal wall generally circular in cross section, a plurality of arcuately aligned rods contiguous one to another and extending longitudinally of and contiguous to and rotatably supported by said longitudinal wall, some of said rods being in direct grinding contact with said longitudinal wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means for maintaining the arcuate alignment of the rods during the rotation of the mill.

2. A drum-type rotary grinding mill having, in combination, a longitudinal wall generally circular in cross section, an end Wall attached to each end of said longitudinal wall to form with the longitudinal wall a grinding chamber, a plurality of arcuately aligned rods contiguous one to another and extending longitudinally of and contiguous to and rotatably supported by said longitudinal wall, some of said rods being in direct grinding contact with said longitudinal wall, a plurality of balllike comminuting elements supported in major part on said rods, means for rotating the mill, and means in said end walls for maintaining the arcuate alignment of the rods during the rotation of the mill.

3. A drum-type rotary grinding mill having, in combination, a generally cylindrical wall, a plurality of arcuately aligned rods contiguous one to another and extending longitudinally of and supported by said cylindrical wall, some of said rods being in grinding contact with said wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means for maintaining the arcuate alignment of the rods during the rotation of the mill.

4. A drum-type rotary grinding mill having a generally cylindrical wall, an end wall attached to each end of said cylindrical wall to form with the cylindrical wall a grinding chamber, a plurality of arcuately aligned rods contiguous to one another and extending longitudinally of and contiguous to and rotatably supported on said cylindrical wall, some of said rods being in grinding contact with said cylindrical wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means in said end walls for maintaining the arcuate alignment of the rods during the rotation of the mill.

5. A drum-type rotary grinding mill having, in combination, a longitudinal wall defining a grinding chamber of frusto-conical shape, a plurality of arcuately aligned rods contiguous one to another and extending longitudinally of and supported by said frusto-conical wall, some of said rods being in direct grinding contact with said frusto-conical wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means for maintaining the arcuate alignment of the rods during the rotation of the mill.

6. A drum-type rotary grinding mill having, in combination, a longitudinal wall defining a grinding chamber of frusto-conical shape, an end wall attached to each end of said longitudinal Wall to form therewith a frustoconical grinding chamber, a plurality of arcuately aligned rods contiguous one to another and extending longitudinally of said grinding chamber and supported by said longitudinal wall, some of said rods being in direct grinding contact with said longitudinal wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means in said end walls for maintaining the arcuate alignment of the rods during the rotation of the mill.

7. A multiple compartment drum-type rotary mill having in combination, a longitudinal wall defining a grinding chamber generally circular in cross section, one of said compartments comprising a longitudinal wall generally circular in cross section, an end wall attached to one end of said longitudinal wall and a screen wall generally parallel to and spaced from said end wall to form with said end wall and said longitudinal wall a grinding chamber, a plurality of arcuately aligned rods in said grinding chamber, the said rods being contiguous one to another and extending longitudinally of and supported by said longitudinal Wall, at least some of said rods being in direct grinding contact with said longitudinal wall, a plurality of ball-like comminuting elements supported in major part on said rods, means for rotating the mill, and means for maintaining the arcuate alignment of the rods during the rotation of the mill.

8. A drum type rotary mill having, in combination, a rota1y grinding chamber comprising a longitudinal side wall generally circular in cross-section with respect to the axis of rotation of said chamber, an end wall attached to each end of said side wall and extending substantially normal to the axis of rotation to form with said wall a grinding chamber, a plurality of arcuately aligned rods within and extending substantially the length of said chamber and defining thereabove a concavity for containing ball-like comminuting members, a plurality of ball-like comminuting members supported in major part in said concavity, and means for rotating the grinding chamber.

9. A drum type rotary mill having, in combination, a rotary grinding chamber comprising a longitudinal side wall generally circular in cross-section with respect to the axis of rotation of said chamber, an end wall attached to each end of said side wall and extending substantially normal to the axis of rotation to form with said wall a grinding chamber, a plurality of arcuately aligned rods within and extending substantially the length of said chamber and defining thereabove a concavity for containing ball-like comminuting members, a plurality of ball-like comminuting members supported in major part in said concavity, means for maintaining the said rods in arcuate alignment during the rotation of the grinding chamber, and means for rotating the grinding chamber.

10. A drum type rotary mill having, in combination, a rotary grinding chamber comprising a longitudinal side Wall generally circular in cross-section with respect to the axis of rotation of said chamber, an end wall attached to each end of said side wall and extending substantially normal to the axis of rotation to form with said wall a grinding chamber, a plurality of arcuately aligned rods within and extending substantially the length or" said chamber and defining thereabove a concavity for containing ball-like comminuting members, a plurality of ball-like comminuting members supported in major part in said concavity, means for maintaining arcuate alignment of part of said rods in grinding contact with said side Wall and one with another during the rotation of the grinding chamber, and means for rotating the grinding chamber.

11. A drum type rotary mill having, in combination, a rotary grinding chamber comprising a longitudinal side wall generally circular in cross-section with respect to the axis of rotation of said chamber, an end wall attached to each end of said side Wall and extending substantially normal to the axis of rotation to form with said wall a grinding chamber, a plurality of arcuately aligned rods within and extending substantially the length of said chamber and defining thereabove a concavity for containing ball-like comminuting members, a plurality of balllike comminuting members supported in major part in said concavity, means in said end walls for maintaining part of said arcuately aligned rods in grinding contact with said side wall during the rotation of the grinding chamber, and means for rotating the grinding chamber.

12. A drum type rotary mill having, in combination, a rotary grinding chamber comprising a longitudinal side wall generally circular in cross-section with respect to the axis of rotation of said chamber, an end wall attached to each end of said side wall and extending substantially nonnal to the axis of rotation to form with said wall a grinding chamber, a plurality of arcuately aligned rods within and extending substantially the length of said chamber and defining thereabove a concavity for containing ball-like comminuting members, a plurality of balllike comminuting members supported in major part in said concavity, means in each end wall for maintaining part of said arcuately aligned rods in grinding contact with said side wall and part of said rods spaced from said side wall and supported in arcuate alignment on said rods in contact With said side wall, and means for rotating the grinding chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,440,002 Bradley Dec. 26, 1922 1,963,970 Cannard June 26, 1934 2,755,502 Herr July 24, 1956 OTHER REFERENCES German application (KL 500 15/10), 1,069,455, Nov. 19, 1959. 

8. A DRUM TYPE ROTARY MILL HAVING, IN COMBINATION, A ROTARY GRINDING CHAMBER COMPRISING A LONGITUDINAL SIDE WALL GENERALLY CIRCULAR IN CROSS-SECTION WITH RESPECT TO THE AXIS OF ROTATION OF SAID CHAMBER, AN END WALL ATTACHED TO EACH END OF SAID SIDE WALL AND EXTENDING SUBSTANTIALLY NORMAL TO THE AXIS OF ROTATION TO FORM WITH SAID WALL A GRINDING CHAMBER, A PLURALITY OF ARCUATELY ALIGNED RODS WITHIN AND EXTENDING SUBSTANTIALLY THE LENGTH OF SAID CHAMBER AND DEFINING THEREABOVE A CONCAVITY FOR CONTAINING BALL-LIKE COMMINUTING MEMBERS, A PLURALITY OF BALL-LIKE COMMINUTING MEMBERS SUPPORTED IN MAJOR PART IN SAID CONCAVITY, AND MEANS FOR ROTATING THE GRINDING CHAMBER. 